Circadian regulation of RPE functions

视网膜色素上皮(RPE)参与许多必需的过程。 维持感光器功能和健康。RPE还参与了对 光感受器外节周转(视盘脱落和吞噬)是一个过程 这已经被证明是在昼夜节律的控制下。我们最近开发了一种 RPE-脉络膜准备，我们可以使用 PER2：：Luc敲入小鼠，转基因小鼠模型中PER2振荡 是通过萤火虫荧光素酶如实报道的。该模型的独特之处在于它既反映了 转录和翻译后事件，提供了一个强大的工具来研究 生物钟在特定的组织和/或细胞中起作用。使用这种新的制剂，我们 已经证明了小鼠RPE包含一个生物钟，它被 神经调节剂多巴胺(DA)。在本提案(具体目标1)中，我们将测试 假设DA通过位于RPE中的D2样受体参与昼夜节律 RPE中的时钟，从而同步杆状外周吞噬的每日猝发 分段磁盘。然后我们将确定DA通过哪些分子机制 同步RPE中的生物钟。在具体目标2中，我们将检验这一预测 D2R信号的去除将影响吞噬的日常节律，从而导致 衰老过程中脂褐素的积累和感光细胞活性的降低。最后，在 具体目标3我们将确定RPE和视网膜内时钟在调节 RPE吞噬活性的日节律。为了达到这个目标，我们将扰乱生物钟 有选择地在RPE和神经视网膜中计时，并在每天的 吞噬的节律。这项研究提案中描述的实验将 确定多巴胺及其相关受体在调节肾上腺皮质激素中的作用 RPE中的昼夜节律以及视网膜/RPE生物钟在 调节RPE吞噬细胞活动的日节律。

The retinal pigment epithelium (RPE) is involved in many processes necessary to maintain photoreceptor function and health. The RPE is also involved in the regulation of the photoreceptor outer segment turnover (disk shedding and phagocytosis) a process that has been shown to be under circadian control. We have recently developed an RPE-choroid preparation in which we can monitor, in real-time, the circadian clock using the PER2::LUC knock-in mouse, a transgenic mouse model where the PER2 oscillation is faithfully reported via a firefly luciferase. This model is unique in that it reflects both transcription and post-translational events, providing a powerful tool to investigate circadian clock function in a specific tissue and/or cell. Using this new preparation we have demonstrated that the mouse RPE contains a circadian clock that is entrained by the neuromodulator dopamine (DA). In the present proposal (Specific Aim 1) we will test the hypothesis that DA, via D2-like receptors located in the RPE, entrains the circadian clock in the RPE, thus synchronizing the daily burst in phagocytosis of rod outer segment disks. Then we will identify the molecular mechanisms by which DA synchronizes the circadian clock in the RPE. In Specific Aim 2 we will test the prediction that removal of D2R signaling will affect the daily rhythm of phagocytosis thus leading to lipofuscin accumulation and reduced photoreceptor viability during aging. Finally, in Specific Aim 3 we will define the roles of RPE and inner retinal clocks in the regulation of the daily rhythm in RPE phagocytic activity. To reach this goal we will disrupt circadian clocks selectively in RPE and neural retina and assess the consequences on the daily rhythm of phagocytosis. The experiments described in this research proposal will determine the role that DA and its associated receptors play in the regulation of the circadian rhythms in the RPE and the role of retinal/RPE circadian clocks in the regulation of the daily rhythm of RPE phagocytic activity.